Filtering



C. R. BAKER FILTERING Sept. 29, 1931.

Filed Jan. 9. 1929 O O 0 O O G 0 O 0 O.

Patented Sept. 29 1931 UNITED STATES 1,szs,33o

PATENT OFFICE CHARLES R. BAKEB, OF WOOD IRIVER, ILLINOIS, ASSIGNOB TO STANDARD GOI- PANY, OF WEI'I'ING, INDIANA, A COBPORATION' OF INDIALN'L FILTERIN' G Application med January 9, 1929. Serial No. 331,216.

The present inlention relates to improyements in the filtration of hydrocarbon oils, and more particularly to filtration operations in connection with the decolorizing of mineral oils with finely divided fullerls earth and like decolorizing materials. In order that the invention may be fully understood, 1t 1s illustrated in connection With a common commercial form of leaf filter having a hinged casing, although, as is obvious, other forms of filtration devices may be employed in carrying out the invention.

Referring to the drawings:

Figure 1 is a side elevation of a portlon of a common commercial type of press, Wlth the lower part of the casing dropped to open position; and 4 Fig. 2 is a seetional view on the line 2 of the press of Fig. 1, likewise shown in open position, together with a spray ldevice employed in carrying out the inventlon.

Referring more particularly to the drawings, the numeral 5 indicates the stationary upper portion of the easing of a filter press mounted on standards 6. The lower portion 7 of the casing is secured to the up er p ortion 5 by hinges 8 and during the 'ltratlon operation, the hinged movable portion 7 of the casing is held in locked position by the swing bolts 9 mounted on eccentrlcs 10 on the lock-shaft 11, locking being eifectedby means of the hand Wheel 12 through gearing i V 13. The lower portion 7 of the casing is provided in the usual Way With the drainage channel 14 and the distributing plate 15, through which feeding is ordinarily efected, and, if desired, in the upper portion of the casin the internal feeding manifold 16 with distri uting nozzles 17 may also be provlded.

The filter leaves 18 are made up, in the usual way, of an outer frame or rim 19, to each side of which is secured the Wire screen or perforated support 20, to the outside of which the filter medium 21 is applied. The filter medium may suitably be textile cloth. The interiors of the leaves communicate with the discharge nozzles 22, and each discharge nozzle 22 is connected by Outlet pipe 23 with the filtrate discharge manifold 24. Since the type of filter described is a common commercial form, a further detailed description thereof vWill not be given.

In the practice of decolorizing mineral oils, and particularly the more viscous lubricating oils by thoroughly mixing a finely divided decolorizing a ent such as fullerls earth with the oil, whic may previously have been treated with sulfuric acid, the oil is subscquently forced through a suitable filtering Idevice, such as -a filter of the t pe above described, to remove the decolorizlng agent from` the oil.

In accordance With the present invention, the filtration operation is markedly improved and the character of the oil resulting from the filtra-tion is likewise improved by preliminarily applying to the filtering medium an extremely thin coating of finely divided inert filter-aiding solids, such as filter-cel, diatomaceipus earth, fullerls earth, filter-clay or the li e. i

4In carrying out the invention, thelfilter-aiding material, such as finely divided, purified diatomaceous earth is suspended in oil, for example, naphtha, mineral seal oil, or oil of the character of that to be Submitted to filtration. This material, which may suitably be 80-300 mesh, is suspended in the oil in a fairly thin suspension; say one part of the filter-aiding material and four parts of oil by Weight.` The suspension may be painted upon the outer surfaces of the filtering medium on the filter leaves, or preferably sprayed upon them, for example, by such a device as that illustrated in Fig. 2 of the drawings. In that figure, the numeral 25 indicates a container for the suspension, provided with an outlet nozzle 26 tol which is secured the fiexible hose 27. To the end of this is secured a longpipe 28 provided at its end with an elbow nozzle 29. A current of compressed air is forced into the container 25 through the pipe 30. The entiredevice is portable, and the spray pipe 28 and nozzle 29 are hand operated to apply the suspension, driven out by the air blast, evenly over the filter medium. In this way, the filter-aidim' material may be applied to the filtering mi dium very rapidly and in an even coating. The amount of filter-aiding material required is relatively small; for example, using a sus- CSI i filtration operation.

The use of the present invention in connection With the filtration of decolorizing materials from hydrocarbon oils markedly increases the efficiency of the filter press, and

prevents the cloudiness of the filtrate normally occurring during the first portion of each filtration operation after removing the filter cake from the preceding operation, this being the portion of the operation during which the rate of filtration is at its maximum. It likeWise markedly facilitates the cleaning of the press, the filter cake being removed more easily after each filtering operation, and prevents leaking through the plates With resulting cloudiness and depreciation of the filtrate. It is likewise found that by the use of the present invention, the properties of the oil filtrate are improved, particularly as to emulsion test, color and clearness, and that there are improyements in its other Chemical characteristics.

Although, for convenience, the invention has been described in connectionvwiththe operation of a leaf-type filter, it is readily apparent that it may be employed in connection With the use of other types of filters, such as the continuous disk or drum filters, or plate and frame presses.

I claim:

1. In the operation of filtering mineral oils admixed With finely dispersed decolorizing material, through a filter medium, the step of improving the 'operation which comprises preliminarily applying to the filtering surface of the filter medium, as a superficial nonpermanent coating, a liquid suspension ,of finely divided filter-aiding material, said application being made prior to beginning filtration of the oil therethrough and While both sides of the filter medium are under substantially the same pressure.

2. In the art of filtering mineral oils containing finely dispersed decolorizing material by passing such oil through a sheet filter element and into the interior of a filter leaf to which said sheet filter is secured, the step of improving the operation which comprises preliminarily applying to the eXterior surface of said sheet filter element, as a superficial non-Permanent coating, a liquid suspension of finely divided filter-aiding material prior to beginning filtration of the oil therethrough and While'the interior and exterior of the filter leaf are under atmospherc pres- Sue.

3. In the art of filtering lubricant mineral oils admixed With finely divided decolorizing material Wherein such oil is forced through a filtering medium,` a body of decolorizing material Collecting on the filter medium as a' filter cake, and removed therefrom, and the Succession of operations repeated, the step of applying to the filtering surface of said filter medium, as a superficial non-permanent coating, a suspension in oil of finely divided filteraidin material, after removal of the cake thererom and before again forcing the oil to be filtered therethrough, said coating application being made while both sides of said filtering medium are under substantially the same pressure.

CHARLES R. BAKER. 

